A series of 3', 6, 7-substituted 2-phenyl-4-quinolones were designed and synthesized as antimitotic antitumor agents. All compounds showed cytotoxic effects (log GI50 I-4.0; log drug molar concentration required to cause 50% inhibition) against the growth of a variety of human tumor cell lines, including those derived from solid tumors such as non-small cell lung, colon, central nervous system, ovary, prostate, and breast cancers, when evaluated ...